9
In the above code, num1 += num2 + num3 is a shorthand notation for num1 = num1 + num2 + num3.
Given,
num1 = 4
num2 = 3
num3 = 2
First, the expression num2 + num3 is evaluated:
num2 + num3 = 3 + 2 = 5
Now the expression becomes:
num1 = num1 + 5
which translates to:
num1 = 4 + 5 = 9